Three painless tips for shedding an unwanted kilogram or two

Wittert, who is also head of the discipline of medicine at the University of Adelaide, recommends patients eat “proper food, unprocessed and not out of a box”, don’t eat much after 7pm or 8pm and let at least 10 hours elapse before they eat again.

He says the stomach takes four hours to empty but many people stretch out dinner to 11pm and then go to bed.

His team has conducted research into restricted eating using mice. “If you feed mice when they should be sleeping and don’t give them any food during what should be their waking hours, it puts them at a metabolic disadvantage. Their metabolism functions abnormally and they gain weight.”

He says every cell in the body has a circadian clock fixed to the light/dark cycle and has a different job for day and night. During the day cells process fuel for energy and at night they busy themselves with growth and repair work. But if food keeps entering the system late into the night, the cells keep processing fuel and their functions become confused.

This happens in mice and whether it plays out long term in humans too is yet to be shown.

On this diet people eat normally for five days a week and restrict their intake on two days. Wittert advises his patients to try to eat at relatively fixed times each day to regulate the mechanisms that set their circadian clock.

He says there is no high-level evidence to support slow eating for weight loss. But observational data is increasing. Late last year, another such study from Japan showed gobbling food was bad for the heart.